Gastrointestinal anti-reflux prosthesis apparatus and method

ABSTRACT

A prosthesis ( 13 ) for implanting in an upper stomach to prevent gastric reflux in an esophagus comprising a tube ( 17 ) made of a biocompatible polymer that is resistant to gastric acid, the tube having an upper end and a lower end, a length, and a generally constant diameter along the entire length thereof, the upper end having means ( 16 ) for securing to the upper stomach, the lower end having at least one slit ( 18 ) to facilitate inversion of the tube during vomiting but to facilitate collapsing of the tube under pressure generated by gastric reflux.

BACKGROUND OF THE INVENTION

This invention relates to medical devices and their use, and moreparticularly to implantable prosthesis apparatus which prevent or reducegastrointestinal reflux.

In my prior U.S. Pat. No. 5,861,036 of Jan. 19, 1999, I disclosed aprosthesis in the form of a flexible tube having a substantially uniformcross section, means for endoscopically placing stitches or clips in ahiatal hernia, and a flexible tubular portion enabling the tube to besqueezed by exerting a pressure on the outer surface thereof in order toprevent reflux of the stomach contents into the esophagus. The priordevice was designed so that food could pass freely through theprosthesis in the direction from the esophagus to the stomach. Theprosthesis disclosed in my prior patent was made of a biocompatiblepolymer optionally containing barium sulphate to make it detectableusing X-rays.

Although the prior prosthesis worked well in most situations, there wererisks that in some cases wherein large chunks of food were swallowed orvomiting occurred, the tube would become dislodged.

In a patent application filed May 20, 2003, PCT/US03/15731, entitledApparatus And Method For Securing A Device To An Internal Wall Of ABiological Lumen, I disclosed an improved clip design which is intendedto prevent the dislodging more effectively than the design disclosed inmy aforementioned patent. However, even the improved clip design may notbe sufficient in all cases for severe vomiting events, and so furtherimprovements were sought.

SUMMARY OF THE INVENTION

The present invention comprises, in one aspect, a prosthesis forimplanting in an upper stomach to prevent gastric reflux in an esophaguscomprising a tube made of a biocompatible polymer that is resistant togastric acid, the tube having an upper end and a lower end, a length,the upper end having means for securing to the upper opening of thestomach, the lower end having at least one slit to facilitate inversionof the tube during a high pressure vomiting event but to facilitatecollapsing of the tube under a level of lateral pressure generated bygastric reflux.

In another aspect, the invention comprises A method of preventinggastric reflux in a patient comprising implanting a prosthesiscomprising a tube having an upper end and a lower end, a length, and agenerally constant sectional diameter along the entire length thereof bysecuring the upper end to the upper opening of the patient's upperstomach and allowing the lower end to hang in the upper stomach, thetube having at least one slit at the lower end and adapted to collapseunder a level of lateral pressure generated by gastric reflux from thestomach, invert during a high level of lateral pressure generated byvomiting so as to permit vomit to exit, and upon reduction of pressureat the completion of the vomiting, the tube to return to thepre-vomiting position.

It is preferable that the prosthesis have one to eight slits, and mostpreferable that it have two slits.

The tube in some embodiments may have a constant sectional diameteralong the entire length thereof from the upper end to the lower end,with the slits having a length of at least about one third of the lengthof the tube from the lower end toward the upper end. The slits in otherembodiments may have a length of between 66% and 95% of the length ofthe tube.

The tube should be made of the biocompatible polymer, for examplemedical grade polyurethane, silicone, or polystyrene-ethylene (PSE).

The length of the tube, from upper end to lower end, is preferably about2 to 10 cm.

As disclosed in my aforementioned PCT application, the prosthesis may besecured to the upper opening of the stomach with clips, preferably atleast three clips, which are opened and closed with an endoscopicdevice.

The advantages of the slit valve are that larger pieces of food can beswallowed by the patient without having the food getting caught in thetubular valve. The valve allows vomiting at lower pressures, such asabout 50 mm of Hg of back pressure and once the valve is reverted, it iseasier for the valve to resume its original position once the patientsdrinks fluids or eats something, therefore eliminating the risk of foodbeing blocked by the valve after vomiting.

As is the case with the prosthesis of my prior inventions, the presentprosthesis is a soft tubular element of a fairly constant section whichwin prolong the esophagus into the stomach. As the stomach has anasymmetrical shape in relationship to the axis of the esophagus, in caseof gastric reflux, the exerted pressure has a oblique direction inrelationship to the axis of the esophagus. Therefore, if one prolongsthe esophagus with a soft tube extending for a certain length into thestomach, in case of gastric reflux the soft tube collapses under theoblique pressure and stops the exit of gastric acid into the esophagus.The tube polymer must be resistant to gastric acids. The dimensions ofthe tube may vary, but preferably the tube has a section diameterbetween 25 and 30 millimeters from one end to the other and a length ofbetween 5 and 10 centimeters, with a thickness of the wall chosen toallow it to collapse under lateral pressure applied to its externalwall, when the level of pressure generated by gastric reflux is reached,generally between approximately 0.2 and 0.6 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a patient's stomach and esophagus with aballoon catheter.

FIG. 2 is a sectional view of a patient's stomach and esophagus with theprosthesis according to the invention being inserted.

FIG. 3 is a sectional view a patient's stomach and esophagus with theprosthesis according to the invention in place and about to be clippedto the esophagus wall.

FIG. 4 is a sectional view a patient's stomach and esophagus with theprosthesis according to the invention clipped to the esophagus wall.

FIG. 5 is sectional view a patient's stomach and esophagus with theprosthesis according to the invention clipped to the esophagus wall andresisting normal gastric pressures shown by arrow 20.

FIG. 6 sectional view a patient's stomach and esophagus with theprosthesis according to the invention clipped to the esophagus wall withthe tube reversed inside out due to large gastric vomiting pressureindicated by arrow 24.

FIG. 7 is a sectional view a patient's stomach and esophagus with theprosthesis according to the invention clipped to the esophagus wall withthe tube in its normal position, with large chunks of undigested food 21passing through.

FIG. 8 is a sectional view of a patient's stomach and esophagus with theprosthesis of the present invention unclipped and being removed by ahook on a removal device 11 on a basket type handle 22 on the top of theprosthesis.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

While many different embodiments of the invention are contemplated andare possible, one embodiment is illustrated herein and in the drawings.

Referring first to FIG. 1, a stomach 19 and esophagus 12 are shown withinsertion device 11 carrying a balloon catheter 10 to widen theesophagus prior to insertion of the prosthesis of the invention.

FIG. 2 shows forceps 14 operating delivery-retrieval wire 15 installingthe prosthesis 13, with the clips 16 shown closed.

FIG. 3 shows forceps 14, wire 15, clips 16, with the prosthesis 13 aboutto be installed at the top of the upper stomach 19 by means of clips 16.The slits 18 in tube 17 are illustrated in this view.

FIG. 4 shows the prosthesis 13 with clips 16 installed in the wall ofthe esophagus at the top of upper stomach 19, with tube 17 hanging intoupper stomach 19, with slits 18 shown.

FIG. 5 shows the tube 17 being closed when gastric reflux pressure 20occurs. The force has an oblique direction in relationship to the longaxis of the tube so that with a flexible wall, the tubular prosthesiswill collapse against the stomach wall and will stop the gastric acidfrom leaving the stomach and reaching the mucosa of the esophagus.

FIG. 6 shows the tube 17 reversing inside out into the esophagus whenintense vomiting pressure, shown by large direction arrow 24, occurs.

FIG. 7 shows the tube 17 in its normal position in the upper stomachwhen large chunks of food 21 are being swallowed in direction 25 andgoing through the prosthesis tube 17, which is made easier and moreefficient due to the slits 18.

FIG. 8 shows the prosthesis 13 being unclipped and removed by means ofremoval device 11, using its hook 23 on prosthesis handle 22, afterunclipping clips 16 from the esophagus wall 12.

The tubular prosthesis 17 can be manufactured using several differenttechniques depending on the biomaterial used, particularly depending onthe viscosity of the biomaterial and the thickness of the wall of theprosthesis. The prosthesis can be manufactured by injection molding,extrusion molding or by solvent casting, which is a method of dippingthe prosthesis in a solution of the biomaterial until the desiredthickness of the wall is obtained. The slits are manufactured after thetube is formed.

While the invention has been described and illustrated in detail,various modifications, alternative embodiments, and improvements shouldbecome readily apparent to those skilled in this art without departingfrom the spirit and scope of the invention.

1. A prosthesis for implanting in an upper stomach to prevent gastricreflux in an esophagus comprising a tube made of a biocompatible polymerthat is resistant to gastric acid, the tube having an upper end and alower end, a length, and a generally constant sectional diameter alongthe entire length thereof from the upper end to the lower end, the upperend having means for securing to the upper opening of the stomach, thelower end having at least one slit to facilitate inversion of the tubeduring a high pressure vomiting event but to facilitate collapsing ofthe tube under a level of lateral pressure generated by gastric reflux.2. The prosthesis of claim 1 having one to eight slits.
 3. Theprosthesis of claim 1 having two slits.
 4. The prosthesis of claim 1wherein the tube has a generally constant sectional diameter along theentire length thereof from the upper end to the lower end.
 5. Theprosthesis of claim 1 wherein the one or more slits have a length of atleast about one third of the length of the tube from the lower endtoward the upper end.
 6. The prosthesis of claim 1 wherein the one ormore slits have a length of between 66% and 95% of the length of thetube.
 7. The prosthesis of claim 1 wherein the biocompatible polymer ismedical grade polyurethane, silicone, or polystyrene-ethylene (PSE). 8.The prosthesis of claim 1 having a length from upper end to lower end ofabout 2 to 10 cm.
 9. The prosthesis of claim 1 wherein the means forsecuring to the upper opening of the stomach is a set of at least threeclips.
 10. A method of preventing gastric reflux in a patient comprisingimplanting a prosthesis comprising a tube having an upper end and alower end, a length, and a generally constant sectional diameter alongthe entire length thereof by securing the upper end to the upper openingof the patient's upper stomach and allowing the lower end to hang in theupper stomach, the tube having at least one slit at the lower end andadapted to collapse under a level of lateral pressure generated bygastric reflux from the stomach, invert during a high level of lateralpressure generated by vomiting so as to permit vomit to exit, and uponreduction of pressure at the completion of the vomiting, the tube toreturn to the pre-vomiting position.
 11. The method of claim 10comprising providing the tube with between 1 and 8 slits.
 12. The methodof claim 10 comprising providing the tube with 2 slits.
 13. The methodof claim 10 wherein the one or more slits have a length of about onethird the length of the tube.